<!DOCTYPE html>
<html lang="zh-CN">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>遍历树节点</title>
    <style>
        *,
        *::after,
        *::before {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        :root {
            min-height: 100vh;
        }

        :root:focus-within {
            scroll-behavior: smooth;
        }

        body {
            min-height: inherit;
        }
    </style>
</head>

<body>
    <div></div>
</body>
<script>
    "use strict"; {
        const foreachTree = (data, callback, childrenName = 'children') => {
            for (let i = 0; i < data.length; i++) {
                callback(data[i])
                if (data[i][childrenName] && data[i][childrenName].length > 0) {
                    foreachTree(data[i][childrenName], callback, childrenName)
                }
            }
        }

        const treeData = [{
            id: 1,
            label: '一级 1',
            children: [{
                id: 4,
                label: '二级 1-1',
                children: [{
                    id: 9,
                    label: '三级 1-1-1'
                }, {
                    id: 10,
                    label: '三级 1-1-2'
                }]
            }]
        }, {
            id: 2,
            label: '一级 2',
            children: [{
                id: 5,
                label: '二级 2-1'
            }, {
                id: 6,
                label: '二级 2-2'
            }]
        }, {
            id: 3,
            label: '一级 3',
            children: [{
                id: 7,
                label: '二级 3-1'
            }, {
                id: 8,
                label: '二级 3-2'
            }]
        }];

        let result
        foreachTree(treeData, (item) => {
            if (item.id === 10) {
                result = item
            }
        })
        console.log('result', result)  // {id: 9,label: "三级 1-1-1"}  
    };
</script>

</html>